Gas turbine scroll mount



April 9, 1963 J. P. SIMON GAS TURBINE SCROLL MOUNT 3 Sheets-Sheet 1Filed Oct. 31, 1960 April 9, 1963 J. P. SIMON GAS TURBINE SCROLL MOUNT 5Sheets-Sheet 2 Filed Oct. 31, 1960 INVENTOR. $44155 I? 374704 April 9,1963 Filed 061;. 31, 1960 J. P. SIMON 3,084,907

GAS TURBINE SCROLL MOUNT ,3 Sheets-Sheet 3 jwmrmacw Arr-reel)! y UnitedStates Patent M 3,084,969? GAS TUREINE SrJRULL MGIJN'I James P. Simon,fincinnati, @hio, assignor to General Electric (Zcrnpany, a corporationof New York Filed-Bet. 31, 196%, Ser. No. 66,281 3 Claims. '(El. 253-39)This invention-relates to a scroll for ducting propelling gases to'a gasturbine and, more particularly, to mounting means for a gas turbinescroll wherein means are provided for non-rigidly supporting the scrollto allow for expansion and contraction of the scroll in response totemperature variation of the propelling gases passing through thescroll.

While this invention may have application in any turbine of the typehereinafter described, one example of the use to whichsuch a'designmay'be put is in vertical take-oif aircraft, wherein a lift fan drivenby a tip turbine provides vertical thrust to the aircraft for ascent anddescent. In this use, turbine buckets carried by the fan blade tips orotherwise supported about the fan periphery are supplied with hotpropelling gases for driving the 'liftfan and thus producing thenecessary thrust for lifting the aircraft, the gases being ducted to theturbine buckets from a gas generator, such as a standard jet enginecombustor, by means of a scroll. In this arrangement, both the turbineand the scroll would be mounted to the samcsurrounding structure suchas, in the example used, the airframe of the aircraft.

sponse to variations in the temperature of the flowing gases. In orderto prevent stresses from occurring in the scroll structure which mightcontribute to a structural failure, it is necessary to provide mountingmeans for the scroll which will permit natural expansion-and-contractionof the scroll over a wide temperature range. Since completelyunrestrained expansion or contraction of the scroll may result in thenozzles or outlets being drawn out of alignment with the turbine bucketswith consequent deleterious effects upon the turbine operation, it isalso necessary that the scroll mounting means guide the scroll expansionor contraction along directions which will assure substantially correctcontinuous alignment of the nozzles and the-buckets over a Widetemperature range.

It is therefore an object of this invention to'provide animproved inletscroll for a gas turbine.

Another object of the invention is to provide an improved mounting meansfor a gas turbine inlet scroll wherein themounting means permits limitedmovement of the scroll-due to natural expansion and contraction over awide 'range of temperatures along predetermined directions in order tomaintain continuous alignment of the scroll outlet openings and theturbine buckets to which the propelling gases are directed.

Briefly stated, in accordance with the illustrated embodiments of theinvention, mounting means are provided for supporting a gas turbineinlet scroll with respect to the turbine at three points. The scroll,which wraps -about at least a sector of theturbine periphery, has a acurved configuration which conforms to the turbine pc- 3,984,590?Patented Apr. 9, 1963 riphery so that gases ducted through the scrollare directed through outlet openings or nozzles spacedalong'the lengthof the scroll against the turbine buckets. An inletopening to the scrollthrough which hot propelling gases enter is preferably centered alongthe length of the scroll and is set radially outward from the turbineperiphery so that it clears the outer edge of the rotating rotor. Afirst support, which in some embodiments may be centered upon the scrollinlet, rockingly connects-the scroll to the surrounding airframestructure. Except for a slight rocking or pivoting of the scrollrelative to the airframe at the point where the first support isattached, the scroll is fixed with respect to the airframe at thatpoint. The scroll is supported on each side of the first support bysecond supports which'allow movement of the scroll relative to thesurrounding airframe'and to the first support along predetermineddirections, the directions preferably being along axes connecting thefirst support to each of the second supports. Thus, expansion of thescroll under the influence of the temperature of the propelling gases ispermitted to take place in the predetermined manner to minimize thepossibility of misalignment-of the scroll outlet nozzles which arepositioned along the arc of the scroll and the turbine buckets which arepositioned in a coinciding arc beneath the nozzles. Thus, with thearrangement of this invention, the second supports located on each sideof the first support permit the scroll togrow outwardly from the fixedpointofsupport along predeter mined lines of movement.

While the specification'conc'ludes with claims particularly pointing outand distinctly claiming the subject matter of the invention, it isbelieved that the invention will be better understood from the followingdescription taken in connection with the accompanying drawings in which:

FIGURE 1 is a fragmentary plan view of a turbine rotor and a partialadmission scroll in their assembled relation with respect to oneanother, the scrollbeing supported by a presently preferred embodimentof'the mounting means of this invention in which the fixed supportcoincides With-the center ofthe scroll inlet;

FIGURE 2 is a partial view taken along line 2-2 of FIGURE 1;

FIGURE 3 is a partial view taken along line-33 of FIG-'URE'Q;

FIGURE 4 is a partial view taken alongline 44 of FIGURE 1;

FIGURE 5 is an alternative embodiment of the mounting supportillustrated in FIGURE 4;

FIGURE 6 is a schematic view of the invention as applied-to a fulladmission scroll; v

FIGURE 7 is a schematic View of two partial" admission scrolls incombination to provide for full admission to the turbine, each scrollbeingsupported-byasupport arrangement of an alternate embodiment of theinvention in which one'of the fixed supports is offset from the centerof the scroll inlet;

FIGURE 8 is a schematic view of a scroll supported by the mounting meansof the invention, in which the scroll inlet is located at-the end of thescroll; and

FIGURE 9"is a plan view, similar to FIGURE 1, illustrating the expansionmovement of the scroll.

Referring first to FIGURE 1, a turbo-fan rotor, generally indicated at1t), is shown having fan blades 11. Carried about the periphery of therotorare a plurality of turbine vanes or buckets 12. An arcuate orannular gas duct inlet scroll, generally indicated at 13, conforms tothecurvature of a sector of the turbine rotor Iii. An

inlet 14 which is radially spaced from-the turbine periphery admitspropellinggasegas shown by the arrows in FIGURES 2 and 3, from asuitable gas generating v.3 means, such as the combustor of aconventional jet engine. Inlet 14 is preferably located equidistantly ofeach end of the scroll 13. The rotor propelling gases admitted throughinlet 14 are ducted throughout the scroll 13 and are discharged throughoutlets or nozzles 12a arranged about the arcuate or curvilinearbifurcated duct portions or branches 15. This portion 1 5 overlies theturbine buckets 12., so that the outlets or nozzles discharge thepropelling gases directly onto the buckets about the sector of the rotorcovered by the scroll.

Centered with respect to the inlet 14 are the parts needed to supportthe scroll. There is a first support 16 rockingly mounting one point ofthe scroll to the airframe or other surrounding structure 17 by means ofthe other part shown. As seen in FIGURES 2 and 3, the support 16 isfixed to the scroll 13 in a crease portion 18 which divides the totalflow of inlet air and directs a portion of the air into each of thebranches 15. Except for a possible slight rocking movement of the scroll13 at the first support point, the first support 16 fixes the positionof the scroll relative to the airframe or other surrounding structure17.

On each side of the first or fixed support 16, there is provided arespective second support 19, mounting the scroll at two points to theairframe or other surrounding structure 17, so that together with thefixed support 16, support of the scroll at three points is provided.Each of the second supports 19 preferably, but not necessarily as shownin FIGURES 6 and 8, located at the ends or extremities of the arcuatescroll are of a non-rigid or movable type to provide limited movement ofthe scroll along a single axis. Each of the second or movable supports19 may be of a sliding type of any suitable form but, as illustrated inFIGURE 4, may take the form of a crosshead arrangement having a fixedbar 26 rigidly mounted to the airframe or other surrounding structure17, and a link or bearing loop 21 adapted for sliding movement along thebar 20. The supports 19 are preferably oriented so that the movement ofthe slidable loops 21 and the consequent movement of scroll branches 15will take place along axes drawn between each slidable support 19 andthe fixed support 16 as shown in FIGURE 1.

As an alternative to the slidable support of FIGURE 4, the nonrigid ormovable support 19 may take the form illustrated in FIGURE 5, wherein asuitable link 23 pivotally connects the scroll 13 to the airframe orother surrounding structure 17 at pivot points 24 and 25, respectively.

It will be understood that the invention can take many forms in additionto the preferred embodiment shown in FIGURE 1. As shown in FIGURE 6, themounting means of the invention can be used to provide a three pointsupport for a full admission scroll as well as for the partial admissionscroll shown in FIGURE 1. The full admission scroll 26 substantiallyentirely encircles the turbine rotor so as to provide gas admission tothe turbine buckets around the entire turbine periphery. A first orfixed support 27 preferably centered upon the inlet 28 rockinglysupports the scroll 26 relative to the airframe or other surroundingstructure. Second or movable supports 29 are positioned on each side ofthe fixed .support 27 and are oriented so that movement of the scroll 26takes place along axes intersecting the fixed support 27 and each of themovable supports 29. Likewise, the movable supports 29 need not belocated at the ends of the scroll branches as shown in FIGURE 1, but maybe located at convenient points along the length of the scroll branches30 as shown in FIGURE 6.

Referring now to FIGURE 7, two partial admission scrolls similar to theone shown in FIGURE 1 can be used in combination in order to provide forfull admission to a gas turbine. Each of the partial scrolls 31 issupported at three points by a first or fixed support 32 and by secondor movable supports 33 spaced on each side of the fixed support.Although the fixed support may preferably be centered upon the inlet tothe scroll as shown in FIG- URE 1, the fixed support 32 is shown inFIGURE 7 in an alternative position in which it is not centered over theinlet 34, but is spaced a substantial distance from the inlet along oneof the scroll branches.

FIGURE 8 shows an alternative scroll embodiment in which an inlet 35 islocated at one end of the scroll 36 rather than in the center of thescroll. The scroll 36 is supported at three points by a fixed support 37and two movable supports 38 spaced on each side of the fixed support. Itwill be understood that the fixed support 37 may be centered on theinlet 35 as shown in FIGURE 8 or may be alternately displaced from thecenter along the length of the scroll as described for FIGURE 7.

Referring now to FIGURE 9, it will be understood that as propellinggases at elevated temperature are admitted to the scroll 13 via inlet 14and are ducted through the scroll to the outlet nozzles 12a duringoperation of the engine, the elevated temperatures to which the scrollis subjected cause it to expand. Being only rockingly mounted to thesurrounding structure at the fixed support 16, the scroll can only growfrom the dotted line position radially outward to the solid lineposition from that fixed support as a center. The movable supports 19permit this natural growth, but control the direction of growth alongpredetermined axes which, while straight or linear as 22, maintain thescroll substantially in alignment with the periphery of the rotor 10 andparticularly with the turbine buckets 12. As an example, two differentlines X and Y are shown. A given point 0, as shown on each of the linesX and Y at the cold dotted position of thescroll, moves in an outwarddirection along the X and Y lines to the point it, which is the hotexpanded solid position of the scroll, showing how the parts aremaintained in substantial alignment. Similarly, contraction of thescroll, as from the solid outline hot position of FIGURE 9 to the dottedoutline cold position, taking place as the flow of propelling gases isdecreased is controlled by the support arrangement so that alignment ofthe nozzles 12a with the buckets 12 is maintained. Thus, the scroll issupported for limited movement in the predetermined directions whichdirections are along the axes intersecting the fixed and movablesupports.

In view of the foregoing, it will be apparent to those skilled in theart that the instant invention provides a means for supporting a gasturbine scroll whereby dimensional change in the scroll due to variationin temperature leaves undisturbed the desired alignment between theoutlet nozzles carried by the scroll through which the gases pass fromthe scroll and the buckets of the turbine rotor against which thepropelling gases are directed, thereby avoiding efiiciency loss or otherdeleterious effects upon turbine performance.

While the foregoing description has illustrated the invention as usingthe cross-head and pivoted link arrangements as the movable support forthe scroll, it will be understood that the invention contemplates anysuch combination of elements wherein the scroll is supported at threepoints, one of which fixes the position of one point of the scrollrelative to the surrounding structure while the other two movablysupport the scroll for limited movement in predetermined directions.Thus, for example, the concept of the invention could be adapted to aninlet scroll in which the inlet aperture is not centered with respect tothe scroll ends as shown in FIGURE 8, or in which the axes of movementof the movable supports does not intersect the fixed support, or inwhich other forms of movable supports than the ones illustrated could beused. It is apparent that still other changes and modifications may bemade in the construction and arrangement of the various parts withoutdeparting from the scope of the invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. For a gas turbine comprising a rotor having a plurality of fluidresponsive elements on the circumference thereof and a surroundingstructure,

an inlet scroll comprising a gas duct,

inlet opening means in said duct,

outlet nozzles along the length of said duct individually aligned withsaid elements,

and a three point support system including a first support substantiallyfixedly supporting said duct at One point and second and third supportseach spaced along the length of said duct from said first support andsupporting said duct for limited movement,

said first support comprising first and sec-ond parts, said first partbeing fixed to said duct and movably connected to said second part, saidsecond part being secured to said surrounding structure, whereby slightrocking motion of said first part relative to said second part ispermitted about a first axis,

said second support including means for confining said limited movementto a path along a second axis intersecting said first and secondsupports,

and said third support including means for confining said limitedmovement to a path along a third axis intersecting said first and thirdsupports,

whereby thermal expansion of said duct caused by hot fluid flowingtherethrough is directed primarily along said second and third axes tomaintain the alignment of said nozzles with said elements.

2. For a gas turbine comprising a rotor having a plurality of fluidresponsive elements on the circumference thereof and a surroundingstructure,

an inlet scroll comprising a bifurcated duct having two arcuatebranches,

inlet opening means in said duct,

outlet nozzles along the length of said branches individually alignedwith said elements, and a three point support system including a firstsupport substantially fixedly supporting said duct at one point andsecond and third supports each adjacent the end of one of said branchesfor supporting said duct for limited movement of the branches,

said first support comprising first and second parts, said first partbeing fixed to said duct and movably connected to said second part, saidsecond part being secured to said surrounding structure whereby slightrocking motion of said first part relative to said second part ispermitted about a first axis,

said second support including means for confining said limited movementto a path along a second axis intersecting said first and secondsupports,

and said third support including means for confining said limitedmovement to a line along a third axis intersecting said first and thirdsupports,

whereby thermal expansion of said branches caused by hot fluid flowingtherethrough is directed primarily along said second and third axes tomaintain the alignment of said nozzles with said elements. 3. For a gasturbine comprising a rotor having a plurality of fluid responsiveelements on the circumference thereof and a surrounding structure,

an inlet scroll comprising a duct,

inlet opening means radially spaced from the periphery of the turbine,

two arcuate branches communicating with and extendfrom said inletopening means around the periphery of said turbine and conforminggenerally therewith,

outlet nozzles along the length of said branches individually alignedwith said elements,

and a three point support system including a first support fixedlysupporting said duct at a point substantially centered upon said inletopening means and second and third supports each adjacent the end of oneof said branches for supporting said duct for limited movement of saidbranches,

said first support comprising first and second parts, said first partbeing fixed to said duct and movably connected to said second part, saidsecond part being secured to said surrounding structure whereby slightrocking motion of said first part relative to said second part ispermitted about a first axis, said second support including means forconfining said movement to a path along a second axis intersecting saidfirst and second supports,

and said third support including means for confining said movement to apath along a third axis intersecting said first and third supports,

whereby thermal expansion of said duct caused by hot fluid flowingtherethrough is directed primarily along said second and third axes tomaintain the alignment of said nozzles with said elements.

References Cited in the file of this patent UNITED STATES PATENTS921,832 Hersey May 18, 1909 1,050,136 Hodkinson Jan. 14, 1913 1,325,135Baumann Dec. 16, 1919 1,373,289 Baumann Mar. 29, 1921 1,379,258 Guy May24, 1921 1,846,550 Gottwald Feb. 23, 1932 2,119,376 Allee May 31, 19382,190,170 Campbell Feb. 13, 1940 2,564,042 Walker Aug. 14, 19512,615,300 Lombard Oct. 28, 1952 2,631,815 Holtzwarth May 17, 19532,800,297 Ergenc July 23, 957 3,004,388 Foulon Oct. 17, 1961 FOREIGNPATENTS 1,200,183 France Dec. 18, 1959

1. FOR A GAS TURBINE COMPRISING A ROTOR HAVING A PLURALITY OF FLUIDRESPONSIVE ELEMENTS ON THE CIRCUMFERENCE THEREOF AND A SURROUNDINGSTRUCTURE, AN INLET SCROLL COMPRISING A GAS DUCT, INLET OPENING MEANS INSAID DUCT, OUTLET NOZZLES ALONG THE LENGTH OF SAID DUCT INDIVIDUALLYALIGNED WITH SAID ELEMENTS, AND A THREE POINT SUPPORT SYSTEM INCLUDING AFIRST SUPPORT SUBSTANTIALLY FIXEDLY SUPPORTING SAID DUCT AT ONE POINTAND SECOND AND THIRD SUPPORTS EACH SPACED ALONG THE LENGTH OF SAID DUCTFROM SAID FIRST SUPPORT AND SUPPORTING SAID DUCT FOR LIMITED MOVEMENT,SAID FIRST SUPPORT COMPRISING FIRST AND SECOND PARTS, SAID FIRST PARTBEING FIXED TO SAID DUCT AND MOVABLY CONNECTED TO SAID SECOND PART, SAIDSECOND PART BEING SECURED TO SAID SURROUNDING STRUCTURE, WHEREBY SLIGHTROCKING MOTION OF SAID FIRST PART RELATIVE TO SAID SECOND PART ISPERMITTED ABOUT A FIRST AXIS, SAID SECOND SUPPORT INCLUDING MEANS FORCONFINING SAID LIMITED MOVEMENT TO A PATH ALONG A SECOND AXISINTERSECTING SAID FIRST AND SECOND SUPPORTS, AND SAID THIRD SUPPORTINCLUDING MEANS FOR CONFINING SAID LIMITED MOVEMENT TO A PATH ALONG ATHIRD AXIS INTERSECTING SAID FIRST AND THIRD SUPPORTS, WHEREBY THERMALEXPANSION OF SAID DUCT CAUSED BY HOT FLUID FLOWING THERETHROUGH ISDIRECTED PRIMARILY ALONG SAID SECOND AND THIRD AXES TO MAINTAIN THEALIGNMENT OF SAID NOZZLES WITH SAID ELEMENTS.